Friday 28 June 2013 06.48 EDT
First published on Friday 28 June 2013 06.48 EDT

The Sam Mendes-directed Charlie and the Chocolate Factory at the Theatre Royal Drury Lane, marks the arrival of the second Roald Dahl musical in the West End. Sadly, Charlie – which is lacking in narrative tension and so dull and tooth-achingly sweet that by the interval I wondered whether I had lapsed into a diabetic coma – is no Matilda. It lacks the gleeful invention that Tim Minchin and Dennis Kelly bring to that story, both in terms of songs and narrative.

Instead Mendes wallops us over the head with Mark Thompson's big, gaudy designs. For a story about the limitless possibilities of the imagination, it is a surprisingly constrained and old-fashioned musical show, and it displays little of Dahl's subversive humour. It tells the story well enough, but the characters appear to have no inner life and, in the case of Willy Wonka himself, no motivations either.

It's a pity, because in recent years books written for children and young people have provided the West End with some of its biggest and most imaginative hits, including War Horse and Curious Incident of the Dog in the Night–Time. What's interesting about these productions is that, just as Julie Taymor's stage version of the Lion King refused to offer a facsimile of the Disney movie but sought to investigate the story's theatrical possibilities, they are faithful to the spirit of the book but not tied too closely to it.

The same was true of the National Theatre's stagings of His Dark Materials and most particularly Jamila Gavin's Coram Boy, directed with wild visual and musical flair by Melly Still. War Horse the novel and War Horse the stage show are both delicious in their own way, but they are also utterly different from each other. It's a reminder that the successful transposition from page to stage is not about dogged faithfulness, but creativity. What these shows often share is a willingness to use radical theatre techniques rather than technology to solve staging problems. The result? Shows with a strong and distinctive aesthetic.

The great thing about many of these titles is that they attract family audiences (although West End ticket prices can be a serious barrier), but also have a cross-over appeal to adults. On Tuesday morning I took part in a very brief discussion on Radio 4's Today programme that asked why these shows – and much literature written for children and teenagers – attracted adult audiences and readers, and whether seeing shows such as Charlie was infantilising for adults.

No, was my response, because the question presumes that somehow something written with children or young people in mind couldn't possibly be as morally or emotionally complex as material written for adults. Shows such as Curious Incident and Matilda have some of our most exciting and serious writers (Simon Stephens, Tim Minchin, Dennis Kelly) and directors (Marianne Elliott and Matthew Warchus) on board. They have produced shows that are as grown-up in their subject matter and execution as anything aimed at adult audiences. It's a pity that Charlie is not in the same league, but it's a timely reminder that putting children's literature on stage is never child's play.